This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Studies of genetic disorders such as fragile X syndrome (FXS) which is a disorder caused by a single gene mutation resulting in abnormal dendritic and synaptic pruning, together with healthy individuals may provide valuable information to study gene, brain-behavior relationship. Specific Aims: To examine morphometric spatial patterns that differentiate between FXS from controls in early childhood. Methods: Voxel-based morphometry was examined in a total of 101 children of ages 1 to 3;51 boys with FXS, 32 typically developing (TD) boys and 18 boys with idiopathic developmental delay (DD).